Trees, shrubs, or herbs, deciduous or evergreen. Stems erect, scandent, arching, prostrate, or creeping, armed or unarmed. Buds usually with several exposed scales, sometimes with only 2. Leaves alternate, rarely opposite, simple or compound; stipules paired, free or adnate to petiole, rarely absent, persistent or deciduous; petiole usually 2-glandular apically; leaf blade often serrate at margin, rarely entire. Inflorescences various, from single flowers to umbellate, corymbose, racemose or cymose-paniculate. Flowers usually actinomorphic, bisexual, rarely unisexual and then plants dioecious. Hypanthium (formed from basal parts of sepals, petals, and stamens) free from or adnate to ovary, short or elongate. Sepals usually 5, rarely fewer or more, imbricate; epicalyx segments sometimes also present. Petals as many as sepals, inserted below margin of disk, free, imbricate, sometimes absent. Disk lining hypanthium, usually entire, rarely lobed. Stamens usually numerous, rarely few, always in a complete ring at margin of or above disk; filaments usually free, very rarely connate; anthers small, didymous, rarely elongate, 2-locular. Carpels 1 to many, free, or ± connate and then adnate to inner surface of cupular receptacle; ovary inferior, semi-inferior, or superior; ovules usually 2 in each carpel, rarely 1 or several, anatropous, superposed. Styles as many as carpels, terminal, lateral, or basal, free or sometimes connate. Fruit a follicle, pome, achene, or drupe, rarely a capsule, naked or enclosed in persistent hypanthium and sometimes also by sepals. Seeds erect or pendulous, sometimes winged, usually exalbuminous, very rarely with thin endosperm; cotyledons mostly fleshy and convex abaxially, rarely folded or convolute.

Many plants of this family are of economic importance and contribute to people’s livelihoods. The Rosaceae contain a great number of fruit trees of temperate regions. The fruits contain vitamins, acids, and sugars and can be used both raw and for making preserves, jam, jelly, candy, various drinks, wine, vinegar, etc. The dried fruits of the genera Amygdalus and Armeniaca are of high commercial value. Some plants in the genus Rosa containing essential oils or with a high vitamin content are used in industry. Rosaceae wood is used for making various articles, stems and roots are used for making tannin extract, and young leaves are used as a substitute for tea. Numerous species are used for medical purposes or are cultivated as ornamentals.

The Rosaceae are very well represented in China, with great economic and scientific importance. The Co-chairs of the Editorial Committee (Wu
and Raven) here note that the patterns of relationship are complex and the group is taxonomically difficult. We consider the following treatment to be
relatively traditional, with some of the generic treatments arguably out of date. The same applies to the arrangement of the subfamilies, among which
the Maloideae may be the most advanced and should therefore appear last. We regard this account, the first comprehensive, English-language treatment
of the Rosaceae of China, as preliminary, but consider it a useful guide for the recognition of species. Significant revisions of various groups
within the family will certainly be necessary as taxonomic studies proceed.